The party said Friday that it would do nothing to help Mark Clayton, 35, who received nearly twice as many votes as his closest challenger in Thursday’s seven-candidate primary, winning the right to challenge Republican U.S. Sen. Bob Corker in November.

“The only time that Clayton has voted in a Democratic primary was when he was voting for himself,” the party said in a news release. “Many Democrats in Tennessee knew nothing about any of the candidates in the race, so they voted for the person at the top of the ticket. Unfortunately, none of the other Democratic candidates were able to run the race needed to gain statewide visibility or support.

“Mark Clayton is associated with a known hate group in Washington, D.C., and the Tennessee Democratic Party disavows his candidacy, will not do anything to promote or support him in any way, and urges Democrats to write-in a candidate of their choice in November.”

Clayton defended his work for Public Advocate of the United States, the pro-life, pro-marriage group in question, and said he was disappointed with the Tennessee Democratic Party’s “zero-sum politics.”

“It’s not necessarily surprising, unfortunately,” he said in a phone interview. “But that’s not the way I deal with my political opponents. I have good friends who are liberals.”

Clayton acknowledged his social conservative instincts but said he’d been deeply disappointed by the presidency of George W. Bush, the last Republican to occupy the White House.

Tennessee Republican Party Chairman Chris Devaney gloated on Twitter about the opposition party’s failure to find a suitable candidate.

“Nice vetting job by the Dems,” Devaney wrote.

The reaction wasn’t any more sympathetic in some Democratic quarters.

“What a debacle in Tennessee,” the liberal Daily Kos website wrote Friday morning, hours before the party announced its decision. “It’s not like Democrats were ever going to have a shot at unseating freshman Sen. Bob Corker, but at least our preferred candidate, actress and activist Park Overall, is a real Democrat. The guy Dems did nominate seems to be anything but.”

Clayton said he’s an unpaid vice president and does occasional writing for Public Advocate of the United States, which was designated as “an anti-gay hate group” by the Southern Poverty Law Center in March. A story on the center’s web site says Public Advocate “has spread lies and vitriol about LGBT people to raise funds, impede progress toward greater equality and to deny LGBT people basic dignity and respect.”

The organization says on its own site that it has worked to support a “federal traditional marriage (man-woman) amendment to the Constitution to defend traditional marriage from assaults from those who claim to promote ‘same sex marriage’.”

Clayton said the group protects “the rights of people who don’t want to live their lives differently.” He said the Southern Poverty Law Center teaches a “gender-bending” curriculum and uses its national list of hate groups as a fund-raising strategy.